Colonic interposition between the jejunum and ileum after massive small bowel resection in rats

Most patients who undergo massive small bowel resection develop the "short bowel syndrome", which usually resolves as intestinal adaptation takes place. Some, in whom adaptation appears to be inadequate, remain severely incapacitated, and attempts have been made to improve absorption using a variety of surgical maneuvers. Successes have been recorded, but the procedures (of which reversal of a segment of small intestine to prolong the intestinal transit time has been most frequently used) are unpredictable and may actually be harmful. This study was designed to evaluate the theory that, because of the slow pattern of peristaltic activity inherent in the colon, the intestinal transit time could be safely and predictably prolonged after massive small bowel resection by transposing a segment of colon to between the jejunal and ileal remnants in an iso-peristaltic direction. The following procedures were performed, using 56 rats: (1) Resection of 80% or 90% of the small intestine. (2) Small bowel resection (80% or 90%) and iso-peristaltic jejuno-ileal colonic interposition. (3) Bowel anastomoses without resection. Intestinal function was subsequently evaluated by studying the following: (1) body weight; (2) blood count; (3) intestinal transit time (by contrast radiography); (4) intestinal absorption of sodium iodide, albumin, triolein and Vitamin B12 (using radioisotopic methods); (5) intestinal morphology. Colonic interposition did not have any significant effect following 80% small bowel resection. After 90% resection, colonic interposition increased the intestinal transit time significantly (p less than 0.001) without mortality or serious morbidity, and did not cause intestinal obstruction or prevent intestinal adaptation. Body weight and intestinal absorption were not increased significantly, but the study was too short to exclude an eventual beneficial effect in terms of body weight. It was concluded that iso-peristaltic colonic interposition is a safe and reliable method of prolonging the intestinal transit time after massive small bowel resection in the rat, thereby increasing the efficiency of absorption within the existing absorption capacity. The procedure has been found to be beneficial in dogs, and for reasons discussed, should be equally effective in man. Adjunctive surgery is not recommended at the time of resection in man, but should be considered if absorption remains severely impaired.